You have a two-storey house. Upstairs there is a light fitting. Downstairs your have 3 switches one of which activates the bulb in the fitting upstairs. 2 of the switches are duds. You can't see the lightbulb from where you stand at the switches. You need to figure out which is the switch that lights the bulb. You can turn on any number of switches but you can only go upstairs to check the bulb is lit ONCE!
How can you be sure you've identified the switch correctly?
Correct! You big spoil-sport! Personally I don't think I'm as bright as the lightbulb. I spent 2 days thinking about it before having to have it explained.
Correct! You big spoil-sport! Personally I don't think I'm as bright as the lightbulb. I spent 2 days thinking about it before having to have it explained.
You have a two-storey house. Upstairs there is a light fitting. Downstairs your have 3 switches one of which activates the bulb in the fitting upstairs. 2 of the switches are duds. You can't see the lightbulb from where you stand at the switches. You need to figure out which is the switch that lights the bulb. You can turn on any number of switches but you can only go upstairs to check the bulb is lit ONCE!
How can you be sure you've identified the switch correctly?